Resolved RegionPath always null

While RS3 seems fine now, RegionPath is having difficulties in OSRS.
Even if the destination is clearly valid (like only a few steps away, no obstacles), RegionPath returns null.
The destination is reachable (using the .reachable() method), and Region.getArea() contains the destination.

The only time it seems to successfully generate a path is when the destination is equal to the players position (basically no path).